Near-Earth orbits are becoming congested as a result of an increase in the number of objects in space—operational satellites as well as orbital space debris. The risk of collisions between satellites and space debris is also growing. Controlling the production of debris is crucial to the sustainable use of space. This article presents background information on space debris, including number, size, spatial distribution, source, and the threat to satellites. It also discusses international efforts to control the debris population, including the development of debris mitigation measurements, active removal of space debris, and space traffic management.